Well I mostly agree but not 100%. It is really easy to train big men. There are only 3 skills that count and two can be done single position. This means that even if you start with a triple average guy and can get just 6 pops a season you can have him at triple sensational in 3 seasons. Who can't do that? Far from impossible is triple respectable, 9 pops a season making the player potentially triple prodigious by age 21. I don't train bigs, and I don't know if anyone has actually achieved this, but it seems frightening.
For point guards things aren't so bad. The can be single position trained in almost everything and a steady diet of OD, passing and 1on1 shoud see them fantastic very soon.
Shooting guards have it much harder, first they have to be mostly played out of position, second they really need 6 skills and third lots of their training is two position.
I won't even begin on small forwards.
I have been in the market all season for bigs and the number of times I have checked players histories to see that they have sold for up to 5 times what they are currently selling for is just crazy. There are plenty of guys being trained every day and being sold. Free agents are really wrecking the economy lets switch them off.